Historically, complete removal of a disc from between adjacent vertebrae resulted in fusing the adjacent vertebrae together. This “interbody fusion” procedure, which is in use today, is a widely accepted surgical treatment for symptomatic lumbar and cervical degenerative disc disease (DDD). The aim of a spinal fusion is to relieve pain caused by a degenerated disc, restore anatomy (disc height and/or lordotic curvature), and immobilize the affected level (fusion). Such implants have mainly been inserted into lumbar and cervical intervertebral spaces between adjacent vertebral bodies through an anterior, antero-lateral (oblique), lateral, extraforaminal, transforaminal, or posterior surgical approach.
In most cases of interbody fusion, the main objective is to relieve pain while preventing iatrogenic injury. Moreover the interbody device should be stable and subsidence resistant. In order to prevent iatrogenic injury during interbody fusion, a minimally invasive approach offers an ideal solution, however, in order to provide stability and subsidence resistance, a large footprint is beneficial. Therefore, a compromise is generally required to achieve both.
While many minimally invasive interbody fusion devices are offered in a fixed shape, some are available that include an expandable footprint. These expandable devices, however, are not ideal and improvements are desired.